Treatment of hydrocarbon resins and products thereof



Patented Feb. 8, 1949 TREATMENT OF HYDROCARBON RESINS- AND PRODUCTSTHEREOF Frank J. Soday, Baton Rouge, La.-, assignor to The United GasImprovement Company, a corporation of Pennsylvania No Drawing.Application June 20, 1944,

a Serial No. 541,266

7 Claims. 1 This invention pertains to the decolorization of hydrocarbonresins.

More particularly, this invention relates to the decolorization ofcertain resins derived by the polymerization, either by thermal and/rcatalytic methods, of the high boiling monomeric hydrocarbon materialseparated in monomeric form from tar formed during the production ofcombustible gas by processes involving the pyrolytic decomposition ofpetroleum oil with or without the aid af catalysts.

I have discovered that the color of such resins may be greatly improvedby a process comprising depolymerization, preferably'in the form of athin layer or film, of the said resin or a solution of the said resin,followed by the re-polymerization of the monomeric material obtained.

The unexpected results obtained as a result of the foregoing processappears to be traceable to the fact that the darker-colored constituentsof the said resin either depolymerize at a slower rate than thelighter-colored constituents, and/or the depolymerization productsresulting from the darker-colored constituents are isomerized to formmonomeric materials capable of polymerization to light-colored resinousproducts.

As pointed out previously, the resins employed in the practice of myinvention are obtained by the thermal and/or catalytic polymerization ofthe unsaturated monomeric material boiling Within the range of from 210to 450 C., and particularly between 219 C. and 359 C and separated inmonomeric form from the higher boiling pitch constituents of tar formedduring the production of gas by processes involving the pyrolyticdecomposition of petroleum oil, either with or without the aid ofcatalysts.

The hydrocarbon constituents of such petroleum tar have usually beenconsidered to comprise residual tar, dead oil, and light oil. Theresidual tar comprises the heavy black pitch constituents of the tartogether with any oilunseparated therefrom. The dead oil comprises oilseparated from the residual tar and boiling higher than say ZOO-210 C.The light oil comprises oil separated from residual tar and boilinglower than say 200-210 C.

It has been discovered that very considerable quantities of such resinforming unsaturated monomeric material abovereferred to, including largequantities of readily heat polymeriza-ble material, may be contained inthe tar produced in the vapor phase pyrolysis of crude petroleum oil ora fraction or fractions thereof, such as, for example, .gas oil orresiduum oil. This 'is' particularly so in the case of petroleum oil gastar produced when the pyrolysis is conducted at relatively hightemperatures, such for example as in the manufacture of oil gas orcarburetted water gas at average set temperatures above 1300 F. and,also, particularly so when the oil pyrolyzed is naphthenic, such as acrude oil classifiable in classes 5 to 7 inclusive, according to themethod of classification described inBureau of Mines Bulletin 291, asmodified by Bureauv of Mines Report of Investigations 3279, or afraction or fractions of such an oil.

The possibility of recovering large quantities of resin formingmonomeric unsaturated material boiling in the deadoil range was longunrealized. This was because the usual distillation procedures for thepurpose of petroleum tar dehydration and/or tar fractionation were suchas to polymerize the readily heat polymerizable monomers boiling in. thedead oil range into heavy polymers,

which were inextricably mixed with the heavy black residual pitchconstituents and lost therein.

In copend-ing application Serial 370,608, filed Decemberlil, 1940, byEdwin L. Hall and Howard R. Batchelder, which has matured into PatentNo. 2,387,259, granted October 23, 1945, such heat polymerizablemonomeric hydrocarbons boiling in the range of from 210 to 450 C andseparated from the heavy black pitch constituents of the petroleum tarare described and claimed, together with heat polymers producedtherefrom.

In copending application 386,232, filed April 1, 1941, by Waldo C. Ault,which has matured ,into Patent No, 2,387,237, granted October 23, 1945,there is described and claimed the production of catalytic resins fromthe heat polymerizable and/or catalytically polymerizabl-e monomerichydrocarbons boiling within the range of from 210 C. to 450 C. andseparated in mono- 'meric form from the heavy black cuts of thepetroleum tar.

In the manufacture of oil gas and carburetted water; gas, the tarproduced is usually in the pitch constituform of an emulsion due to thecondensation of hydrocarbon constituent-s from the gas in the presenceof water simultaneously condensed from the gas, or otherwise present.

In copending application 342,735, filed June 27,1940, by Edwin L. Halland Howard R. Batchelder, which has matured into Patent No. 2,366,899,granted January 9, 1945, there is described a method'of dehydrating suchpetroleum tar emulsions and of fractionating the hydrocarbonconstituents thereof by rapid distillation,

Number maybe employed.

with the separation from the heavy pitch constituents of residual tar ofsuch heat polymerizable unsaturated monomeric hydrocarbons boiling inthe dead oil range. i

In copending application 353.034, filed August 1'2, 1940, by HowardBatchelder, which has matured into Patent No. 2,383,362. gran-ted August 21, 1945, there is described the dehydration of such petroleum taremulsions and the fractionaticn of the hydrocarbon constituents thereof,with the recovery of monomeric unsaturated heat polymerize-hie dead oilconstituents separate from the heavy black pitch constituents ofresidual tar, by the solvent extraction of the emulsion with ahydrocarbon solvent such as liquefied propane or butane.

Other processes, for example fractional condensation, might be employedto recover these relatively high boiling unsaturated hydrocarbons inmonomeric form and separate from the heavy black pitch constituents ofthe tar. Also processes for oil pyrolysis which avoid the formation ofemulsions, may be employed for the production of the monomeric material.Furthermore, while it may be preferred to employ for pyrolysis petroleumoils or cuts therefrom, which are classifiable in classes 5 to 7inclusive according to Bureau of Mines Bulletin 291, modified asindicated above, and particularly in class '7, other oils Whateverprocess of oil pyrolysis is employed in the production of this monomericmaterial and whatever process is employed for separating the resultanttar, a very important factor is the ercise of care in the treatment ofthe tar in order to avoid excessive polymerization of these readily heatpolymerizable dead oil constituents and their loss as polymers, mixedwith the heavy black pitch constituents of the residual tar.

As a result of separation of the light oil and dead oil components ofthe products of such petroleum oil pyrolysis from the residual tar,without polymerization or with materially reduced polymerization, asubstantially pitch-free hydrocarbon material may be separated having aportion boiling within the range of from 210 to 450 0., and particularlywithin the range from 210 C. to 350 0., which may contain from 5% to30%, and higher. of monomeric unsaturated hydrocarbons readilypolymerizable by heat.

The particular concentration of this heat poly merizable monomericmaterial obtained in a given case will depend upon the amount ofpolymerize tion produced in separating it from the residual tar, as wellas upon such factors as the condition of. pyrolysis and the character ofthe petroleum oil pyrolyzed.

As previously stated, the above mentioned heat polymenzable monomericmaterial may be readily polymerized by heat to form valuable resins,

Polymerization may be efiected by heating the total material separatedfrom the residual tar suificiently to polymerize the readfly heatpolymerizable monomers boiling within the range of from 210 to 450 0.,but insufiiciently to appreciably polymerize the heat polymerizablematerial contained in lower boiling ranges, such, for instance, asstyrene and the methyl styrenes. This may be accomplished, for example,by heating with stirring for 4 hours at 200 0., followed by distillationunder vacuum to isolate the resin.

It may be preferable, however, to first efiect a separation byfractional distillation between light oil boiling below, say, 210 0.,and dead oil boiling.

above, say, 210 C.

The heat polymerizable monomeric material boiling within the range of210 to 450 C. is so readily polymerizable by heat, that, in thefractional distillation of the light oil from the oil, a portion of themonomeric material is usually unavoidably polymerized and remains aspolymer dissolved in the other constituents of the dead oil after thelight oil is taken oiT overhead.

The polymerization of the heat polymerizable unsaturated monomericmaterial in the separated dead oil may be effected by heating the deadoil with stirring; for example, for four hours at 200C.

The resin thus produced, together with any resin produced during theseparation of the light oil from the dead oil, may then be isolated bydistillation under vacuum.

In the separation of lower boiling hydrocarbon material from the pitchconstituents of residual tar by various methods, the oil separated maycon tain components boiling above 350 C. and there may be present heatpolymerizable monomeric material boiling outside the range of from 210C. and 450 0., together with the monomeric material boiling within thatrange. On polymerization, therefore, the resin may include polymersderived from monomers boiling outside of the said range along withpolymers derived from monomers boiling within the said range.

As hereinbefore stated, after polymerization the resin may be isolated bdistillation in vacuum, which may be assisted by steam. The yield,melting point, and other characteristics of the resin will depend uponthe extent to which the isolation has been carried, or, in other words.

upon the proportion of associated oils left in the resin.

Exhaustive steam distillation of the resins obtained from theunsaturated monomeric material *1 isolated from tar by the distillationor solvent extraction methods described herein have produced resinshaving melting points as high as from 185 C. to 200 C. and higher, cubein mercury, as determined by thcmethod and apparatus described in A. S.T. M. Procedure Dill-24, with the following modifications.

1. Mercury is employed in depth of 2 inches instead of water.

2. The cube of resin is rigidly supported by clamping the hook uponwhich the resin is attached so that the top of the cube is 1 inch belowthe surface of the mercury.

3. A 1 inch immersion thermometer is emplayed and is immersed to thatdepth.

4. The exact temperature at which the resin becomes visible at thesurface of the mercury is recorded as the softening point of the resin.

'5. The melting point of the resin is calculated a from the softeningformula.

Melting point C. Softening point C. 1.25+ 2 C.

point by the following The melting point of the resins described in thisspecification is intended to mean melting point as determined by theabove recited method.

unless otherwise specified.

Lower melting point resins may be readily obtained in greater yields byless exhaustive removal of the associated oils, thus resins ranging fromvery soft to hard resins having high melting points may be obtained asdesired.

It has been usually found that each 6% of associated oils left in theresin lowers themelting point about 10 C. I I Heat resins having meltingpoints of C.

have been readilyproduced in yields correspond- 3 ing to 20 to 30% ofthe dead oil in the case of the tar distillate produced in accordancewith the process described in copending application, Serial No. 342,735,and resins of the same melting point have been obtained in yields ashigh as 60% of the dead oil in the case of dead oil separated fromextract produced in the process described in application Serial No.353,034.

The heat polymerizable unsaturated monomeric material is preferably insufiicient concentration in that portion of the hydrocarbon materialseparated from the residual tar which boils within Approximately 1000grams of dead oil derived from the rapid distillation of oil gas tar inaccordance with the process described in said copending application,Serial No. 342,735, and subsequent separation of the distillate, wasweighed into a 2-liter S-necked flask equipped with a thermometer and ashort reflux condenser. The oil was then slowly stirred and heated overa Bunsen burner at a liquid'temperature of 200 0. (110 C.) for a periodof 4 hours.

At the conclusion of this period, the material was allowed to coolsomewhat and Was then transferred for distillation to a tarred 2-literflask equipped with a ground glass neck.

The oil was accurately weighed at this point.

The flask was provided with means for measurlug vapor temperatures, andwas connected with condensing apparatus and with means for providing avacuum,.including a pressure control de vice. Bumping duringdistillation was avoided by folding several folds of iron wire to suchlength that one end reached slightly into the neck of he flask while theother end rested on the bottom of the flask. Y

The pressure was reduced to 100 mm. Hg, absolute, and heat applied bymeans of a Bunsen burner. The distillation was continued at a ressure of100 mm. Hg, absolute, until the vapor temperature reached 180 C. Duringthis first stage of the distillation, careshould be exercised to preventcrystallization-of naphthalene, if presout, such as by employing acondenser operating at elevated temperatures.

When the vapor temperature reached 180 C. at a pressure of 100 mm. Hg,absolute, the flange was lowered-and the pressure gradually reduced to20 Hg, absolute, using care to avoid bumping. When a pressure equivalentto 20 mm. Hg, absolute, was reached, the pressure was maintained at thatvalue, and the distillation continued until a vapor temperature of 195C. was reached.

During the second stage, the condenser may be coo-led by cold water, butcare should be taken to avoid the solidification of anthracene, ifpresent.

The distillation was conducted rapidly, 5 cc. of oil per minutebeingremoved. j

.When. avapor temperature of -.195fC."was re'ached,"the source of heatwas'removed and air was permittedto enter the apparatus slowly untilatmospheric balance was'restored.

In the above operation the yield of resin was 29.3%, with an actualmelting point of 128 0.,

'which was calculated to be equivalent to a yield of 31.4% at a meltingpoint of 120 C. The resin was brown in color.

A straight run A. S. T. M. distillation of 100 cc. of the original oilgave the following data:

First drop C 194 5 cc. C 212 10 cc. n C 223 20 cc C 234.5 30 cc C 242.550 cc C 256.5 70 cc C 283.0 cc. C 319.0 Decomposition point C 319.0Total distillate cc 87 Density at 20 C 1.0107

As pointed out previously, the high boiling monomeric material derivedfrom tar obtained in the pyrolysis of petroleum, by rapid distillationor solvent extraction methods, may be polymerized to form resins of thetype desired by the application of certain catalysts, either with orwithout the simultaneous, or otherwise, application of heat.

Catalysts such as mineral acids, for example, sulfuric acid, hydro-genchloride, acids of phosphorus, or acid acting metallic halides orcomplexes of said halides, preferably organic solvent complexesas forexample, boron trifluoride, aluminum chloride, boron trifluoride-diethylether complex, boron trifiuoride-demethyl ether complex, borontrifiuoride-phenyl other complex, boron trifluoride-phenyl methyl ethercomplex, boron trifluoride-dioxan complex, boron trifluoride-toluenecomplex, corresponding aluminum chloride complexes, and the like, may beemployedfor this purpose.

The metallic halides and their complexes employed are characterized bytheir ability to hydrolyze in the presence of water to give an acid re-A sample of the oil to be polymerized, say 500 00., is poured into atwo-liter 3-neck flask equipped with a thermometer and stirrer. To theoil is added 96% H2804 while agitating vigorously. The acid is added 1cc. at a time and the temperature is not permitted to exceed 50 C. Theaddition of the acid is continued in this manner until no furthertemperature rise is noted. The amount of acid necessary to achieve thisend has been found to be about 1%, by volume, of the oil present.

The oil then is diluted with approximately an equal volume or naphtha,toluene, or similardil' uent, and the solution decanted into 500 cc, of

war water (approximately 60 0.), leaving the acid sludge behind.

After settling, the water layer is drawn off, and neutralization of theacid is accomplished by use of a to 20% aqueous solution of sodiumhydroxide. After washing with caustic, an additional water wash may bemade. In either case, the resin solution is dried by filtration througha bed of a suitable drying agent, such as If desired, the diluent may beadded before polymerization instead of after polymerization.

After neutralization and drying, the resin may be isolated from theunpolymerized oil by any desired method, or the resin may beconcentrated therein by vacuum distillation, which may be assisted byThe melting point of the resin and the yield obtained will depend, amongother things, upon the extent to which the resin has been removed fromthe unpolymerized oil.

Furthermore, the addition of other materials to the heat polymerizablemonomeric unsaturated materials prior to polymerization or to the resinsafter polymerization may, of course, modify the properties of the resinsproduced. Examples of such materials are other synthetic or naturalresins, plasticizers, softeners, fillers, coloring materials, etc.

The resin employed may comprise mixed polymers of monomeric materialboiling within the range of from 210 C. to 450 C. together, if desired,with polymers of monomers boiling outside of this range, or resins maybe employed which are produced from monomers boiling within a selectedrange or ranges within the range of from 210 C. to 450, 0., for instancefrom separated material boiling above say 250 C. or say above 230 C.

The extracted oils may, for example, be distilled prior topolymerization to give a high boiling fraction and a low boilingfraction, which may be polymerized separately. In general, it has beenfound that the resins obtained from the low boiling fraction, that is,the oils boiling below, say, 300-325 0., or even lower, usually aresubstantially lighter in color than the corresponding resins obtainedfrom the high-boiling fraction. The use of such light colored resins maybe preferred for certain of the applications disclosed herein Inseparating such material, the dead oil containing the monomers may befractionated by distillation under vacuum, assisted by steam to avoidundue polymerization during the separation, or other methods ofseparation may be employed.

As previously pointed out, the herein described resins, namely, thoseobtained by the thermal and/or catalytic polymerization of theunsaturated monomeric material recovered from the tar formed during theproduction of gas by processes involving the pyrolytic decomposition orconversion of hydrocarbon oil, with or without the aid of catalysts, maybe decoiorized by a process comprising depolymerization, followed byrepolymerization of the monomeric material obtained. Therepolymerization may be carried out by any of the methods described, orotherwise.

The initial depolymerization step may be carried out by batchdepolymerizing methods, although I greatly prefer to employ methods inwhich a thin film or stream of the resin is depolymerized.

A solution of the resin also may be employed in the depolymerizingoperation, in which case a solvent in which the resin is readily solubleand which is substantially inert to the resin and its monomers ispreferred. Examples of suitable solvents are hydrocarbon solvents, andparticularly aromatic hydrocarbon solvents, such as benzene, toluene,xylene, or solvent naphtha.

Thus, a mixture of solvent and resin may be melted by the application ofheat. By the use of this method, relatively small quantities of solventand moderate temperatures may be employed in the production of a. liquidmixture to be introduced into the depolymerizing unit.

However, I generally prefer to use polymer solutions which are liquid atroom temperature, as such solutions may be handled with less difiicultythan solutions containing less polymerizable solvent.

The depolymerization of the resin or resin solution may be carried outin the presence or absence of certain other diluents in the reactionzone, such as steam, saturated or non-polymerizable solvents,particularly relatively low boiling non-polymerizable solvents such aspropane, butane, pentane, petroleum ether, benzene, and toluene, andinert gases, such as nitrogen, carbon dioxide, stack gases, and thelike. These diluents may be heated or superheated prior to theirintroduction into the reaction zone, in which case they may be used asthe sole source of heat in the reaction zone, or they may be used inconjunction with the external application of heat thereto, or otherwise.

The use of steam is particularly desirable.

Preferably steam (or other diluent) is supplied in ratio of at least 1part of steam (or other diluent) to 10 parts of resin by weight, suchas, at least 1 part of steam (or other diluent) to 2 parts of resin byweight, and more particularly, at least 1 part of steam (or otherdiluent) to 1 part of resin by weight. Usually the ratio of steam (orother diluent) to resin rarely exceeds 5 parts steam (or other diluent)to 1 part resin by weight, or more particularly 3 to 1, or 2 to 1.

However, higher or lower ratios may be employed.

The depolymerizing operations may be carried out at atmospheric,sub-atmospheric, or superatmospheric pressures. In general, atmosphericor sub-atmospheric pressures are preferred.

In addition to being introduced into the reaction vessel in solutionform, the resin may be introduced in molten condition in the absence orsubstantially complete absence of solvent, or introduced in the form offinely divided particles or powder.

As the resin is thermally stable at temperatures below 200 C.,temperatures above this point normally should be employed in order toobtain satisfactory yields of monomer within a reasonable period oftime. I have found that the use of temperatures above 300 C. and,particularly, above400 C., and still more particularly above 450 C., arevery satisfactory for the production of monomer according to the methodsdescribed herein. Temperatures up to 550 or 600 (3., or above, giveexcellent yields. When temperatures above 800 C. are employed, especialcare should be exercised to keep contact time sufficiently short toavoid undue side reactions and/or decomposition of the resin beyond themonomeric state.

Usually the monomeric material is withdrawn from the reaction zonesubstantially as rapidly as formed.

The desired resin or resin solution may be charged to the reaction zoneby any desired method. Thus, for example, the resin or resin solutionmay be pumped into the reaction zone, or it may be vforced into thereaction zone by the application of pressure, or it may be drawn intothe reaction zone by reducing the pressure therewhich steam or any otherdesired heating medium may be passed, or by the use of electricalresistance heaters for this purpose, or otherwise.

The resin or resin solution may be heated to any desired temperatureprior to its introduction into the reaction zone, if desired. Thus, forexample, it may be heated to an incipient decomposition temperature, oralmost to this 'point, before being introduced into the reaction zone.In case a relatively low boiling solvent is present, the resin-solventmixture may be heated under a pressure suificient to maintain thesolvent in the liquid state at the chosen temperature prior to itsintroduction into the reaction zone.

An alternative method of introducing the resin or resin solution to thereaction zone comprises carbureting it with steam, a solvent or otherliquid in the vapor state, an inert gas, or other suitable agent. Thismethod is especially applicable to relatively low-melting polymers, orsolutions thereof, possessing an appreciable vapor pressure attemperatures below their initial depolymerizing temperature. Thus, forexample, a solution of the resin in a solvent may be heated to atemperature of, say, 200 C. in a suitable vessel. A suitable carburetingmedium such as, for example, superheated steam is passed through theheated liquid resin solution, the mixture of steam and carburettedpolymer solution then being delivered to the reaction zone. By asuitable control of the type of resin or resin solution em ployed, thetemperature to which it has been heated, and the temperature of thesteam employed for carbureting purposes, almost any desired ratio ofsteam and resin may be delivered to the reaction zone.

Fairly high boiling solvents preferably should be employed for thispurpose and/or the solvent present in the carburetor replenished fromtime I to time. A relatively low melting type of resin also ispreferably employed. Otherwise, the solvent may be removed completelyfrom the car buretor before all of the resin has been charged to theunit.

I the foregoing methods, the resin or resin solution may be delivered tothe reaction zone in the form of a thin layer or stream, or in the formof a spray or mist of finely divided particles, depending, upon otherthings, upon the type of fitting employed at the termination of thedelivery pipe or other device in the reaction zone.

As pointed out previously, I have discovered that resin or resinsolutions of the type described may be readily depolymerized to givegood yields of monomeric material by the application of heat, preferablyto only a limited quantity of such resin or resin solution at any giventime.

Thus, for example, the resin or resin solution may be introduced into aheated vessel provided with a stirring device conforming to the interiorthereof and sufficiently close to the sides of the vessel to prevent anyundue accumulation of material thereon. In general, vessels of this typeprovided with a stirrer or scraping device extend- 10 I ing over themajor portion of the interior surface of such vessels, particularly thelower portion thereof in the case of vertical vessels, are well adaptedto the production of monomeric material by thermal depolymerization. Ingeneral, the clearance between the heated walls of such vessels and theagitator or scraper should preferably be less than A" and, morepreferably, less than Excellent results are obtained when the clearancebetween the two surfaces is 1 6" or less, and optimum results may beobtained when the agitator or scraper actually scrapes the interiorsurface of the reaction vessel. Thus, for example, vessels of the typecommonly employed the petroleum industry for blending or compoundinggreases, and in which the agitator scrapes the rounded bottom and thelower portions of the sides of the reaction vessel, are Well adaptedto'the preparation of monomeric material by thermal depolymerizationmethods.

In operation, the vessel is heated to the desired temperature, afterwhich the resin, or a mixture of the resin and one or more other agents,such as a solvent, preferably one having a, low boiling point, steam,and/or an inertgas, is introduced into the reaction vessel at anydesired rate. The resin or resin solution is distributed on the bottomand sides of the reactor by means of the agitator blade, the rate offiow of the resin and the depolymerizin temperature usually being soregulated that only a thin film of resin is present on the bottom andsides of the reaction vessel at any given period of time.

It will be understood, of course, that the fore going units only serveto illustrate one method of realizing the advantages of theinvention andare not to be construed as limiting it in any way. In general, anymethod of depositing a-relatively thin layer of the desired resin orresin solution upon a suitably heated surface'will serve to depolymerizethe polymer'in a satisfactory manner.

Another suitable method for the depolymeriza tion of resins or resinsolutions of the type described comprises contacting with a moltenmetal, alloy, salt, mixture of salts, or other liquids cape-- ble ofwithstanding relatively high temperatures without appreciabledecomposition.

An excellent method for the depolymerization of resinous polymers of thetype described corn prises the application of heat thereto while in avery finely divided form. Any desired method of subdividing the polymersolution may be employed, such as pumping or forcing the polymersolution through a suitable nozzle, orifice, constriction, or fittingdesigned to subdivide the stream into a relatively large number ofsmall, discrete particles. Other methods of accomplishing this purposemay, of course, be used if desired. Thus, for example, the resin orresin solution'may be pumped, flowed, or otherwise delivered to the topof a suitable tower or vessel and permitted to flow over a perforatedplate or screen, or both, or otherwise, in such manner as to dispersethe material in the form of very thin streams, or drops, or otherwise. e

Other methods and devices suitable 'for con tacting the finely dividedresin or resin solution may, of course, be employed. Thus, for exam m,the reaction vessel or tower shown may be conical in shape in order toprevent or retard any undue accumulation of polymer on the sides of thevessel. Other refinements will, of course, beapparcut to those skilledin the art. r Another suitable method of depolymerizing resins orresin'solutions is to pump; blow or other;

wise force such materials through a tubular unit possessing a fairlynarrow cross-sectional area, preferably while the resin is in a finelydivided or vaporized form, or otherwise. A pipe coil, tube bundle, orconventional cracking furnace may be used for this purpose withexcellent results.

Other methods familiar to those engaged in the pyrolysis of petroleummay be used if desired. other types of furnaces also may be employed,such as the de Florez furnace, a tube coil immersed in a molten metalbath, and the like.

In addition, the resin or resin solution or admixture may be charged toa conventional gas set, or a modification thereof, such as thoseemployed for the production of blue gas, oil gas, carburetted water gas,and the like. 7

Other methods based upon heating a stream of finely divided resin orresin solution, either alone or in conjunction with one or moreassisting agents such as steam, another solvent, a gas, or a mixturethereof, may be used, if desired.

It is to be understood, also, that any combination of the foregoingdepolymerizing methods may be used for the production of the saidmonomeric material,

In addition, any of the refinements or special methods discussed inconnection with any of the foregoing units may be used in conjunctionwith, or in combination with, or otherwise with, any of the other unitsdescribed.

The method of condensing and cooling the depolymerized, and other,materials obtained also is important from the standpoint of obtaininggood yields. The vapors preferably should be condensed and cooled asrapidly as possible in order to prevent any recombination and to preventside reactions from occurring to any substantial degree. This may beaccomplished by conducting the Vapors into an efficient condenser andcooling as quickly as possible, a satisfactory condenser for thispurpose being a water cooled shell and tube condenser. The depolymerizedmaterials also may be shock-cooled if desired, such as by injecting aspray or stream of water or other cooling medium directly into thedepolymerized products obtained from the reaction zone, or by passingthe depolymerized products through a wash box filled with water, orotherwise.

In general, it may be said that the best results are obtained when theresin or resin solution is depolymerized in the form of thin films orsmall discrete particles or streams in the shortest possible period oftime, then condensing and cooling the depolymerized products in theshortest possible period of time. Any undue increase in thedepolymerizing time, or the time required to condense and cool thedepolymerized materials, may be reflected in decreased yields and in thepresence of substantial quantities of higher boiling oils and otherundesirable by-products in the product obtained.

The steam, non-polymerizable solvents, gases, or mixtures thereof, whichmay be charged to the depolymerizing unit with the resin assist in thereaction in many ways. They may serve to transmit heat directly to theresin, to assist in sweeping out the products of the depolymerizationfrom the reaction zone in the shortest possible period of time, and toserve as diluting agents, thus preventing, or reducing the rate of, thecombination of the polymerizable materials present. 7

pointed out previously, also, thesteam, sqlv ntv pors ga e r; mixtureshereof. used; as

assisting agents in the depolymerization may be preheated to any desiredextent before bein added to the polymer solution or introduced into thereaction zone, or otherwise, and such agent or agents, may be used asthe sole source of heat, if desired.

By the use of the foregoing preferred methods for the depolymerizationof resins of the type described, all of which are based upon theprinciple of exposin a limited quantity of the said resin to elevatedtemperatures for a limited period of time under conditions designed toeffect a rapid transfer of heat from the heating surface or medium tothe resin, removing the dep-olymerized materials from the heating'zone,and condensing and cooling them as rapidly as possible, excellent yieldsmay be obtained.

The depolymerization is preferably carried out in a relatively shortperiod of time. The application of elevated temperatures to the resinfor prolonged periods of time, such as may be encountered, for example,in batch depolymerizing methods, may result in the conversion of arelatively large proportion of such polymers into high boiling oils andsimilar undesirable impurities. In general, it may be said that the timeof depolymerization is a function of the depolymerizing temperatureemployed. By the use of the proper type and size of unit, the contacttime in the depolymerizing zone preferably rarely exceeds 10 minutesand, in most cases will not exceed 5 minutes. Contact timessubstantially under 5 minutes and, more particularly, under 1 minute,will be found to give excellent results.

The process may be more particularly described by means of the followingexample.

Example 3 A heat resin of polymer produced as described in Example 1 ischarged to a depolymerizing unit comprisinga vessel provided with anagitator and containing SllfilClBIlt lead to form, when molten a surfaceapproximately Va below the level of the agitator. The vessel is heatedto a temperature of 650 C. and the resin is charged at a rate sufficientto maintain a depth of 1" on the surface of the lead in the vesselduring the course of the depolymerization. The depolymerized productsare drawn off from the vessel and are condensed and cooled substantiallyas rapidly as formed. The resulting monomeric material obtained isrepolymerized by the application of heat at 200 C. (i10 C.) in the samemanner as the original polymerization was effectedin Example 1. Aresulting heat polymer resin very much lighter in color than theoriginal resin is obtained.

To summarize, the hydrocarbon polymers or resins to which this inventionrelates may be characterized as follows:

(1) The polymers or resins are comprised of carbon and hydrogen inchemical combination to at least 98% and more particularly, to at least99%, other elements such as oxygen, nitrogen and/or sulfur derived fromthe oil pyrolyzed, if present, being restricted to less than 2%, andmore particularly to less than 1%.

(2) The polymers or resins are substantially completely soluble in anexcess of benzene, the proportion of insoluble material being less than1%, and more particularly, less than,0.1% of the polymer or resin.

(3) The polymers or resins have an ash content determined'by burning ofless than 1%, and moreparticularly, ofless than 0.1%.

(4) Upon: subjecting the: polymers: or resins to (a) They have A. S. T.M. ball and ring softening points of at least 40C. and more particularlyof at least 80 C. For example, typical polymers or resins polymerized bysurface active agents such as clay, as catalysts, have A. S. T. M. balland ring softening points of at least 40 C., such as between 60 C. and80 C. or above, and typical polymers or resins polymerized by heat, orwith acid or acid-acting catalysts, have A. S. T. M. ball and ringsoftening points of at least 80 0., such as between 90 and 110 C. andhigher, such as up to 120 C. or above.

(b) They have densities of at least 1.10 and up to 1.20 and higher, suchas between 1.13 and 1.18, as determined by the water displacementmethod.

(0) They have molecular weights between 300 and 1000' as determined bythe freezing point de pression method employing benzene as the sol vent.

(11) They have a solubility in an equal quantity by weight of toluene ata temperature of 20 C. of at least 30 grams, and preferably of at least50 grams, in 100 grams of toluene.

(e) One part of the polymers or resins when dissolved in three parts byweight of benzene having a density (d 20/4) of 0.8790 and a refractivityintercept of 1.0623, makes four parts of a solution having a densitygreater than 0.925 and a refractivity intercept greater than 1.069.Neglecting any possible change that may occur in the solid when it isdissolved, calculated values for the polymers or resins themselves, thatis, apart from the solvent, (densities and refractivity intercepts beingadditive on a volume basis) become for densities at least 1.10, and forrefractivity intercepts at least 1.08, and particularly, at least 1.09,and still more particularly, at least 1.10.

(6) The oils from which the polymers or resins are polymerized havemixed aniline points below 15 0., and more particularly, below 10 C.,for example, between 10 and 4 C. and lower. A mixed aniline point of agiven oil is defined as the critical solution temperature of a mixtureof 10 cc. of anhydrous aniline, 5 cc. of the oil being tested and 5 cc.of a petroleum naphtha having an aniline point of 60 C., as determinedby A. S. T. M. tentative standard D 611-41T.

(7) The oils from which the polymers or resins are polymerized usuallyhaving refractivity intercepts of not less than 1.08, for example,between 1.09 and 1.11, and higher, such as, up to 1.125 or 1.135.

(8) The oils from which the polymers or resins are polymerized containat least 90%, such as not less than 95%, and more particularly not lessthan 97% of aromatic hydrocarbons.

(9) The oils from which the polymers or resins are polymerized havedensities of not less than 0.95, and, more particularly, of not lessthan 0.98, for example, between 0.99 and 1.02, and higher, such as up to1.11. or 1.12.

(10) Liquid material extracted from the polymers or resins using a largeexcess of pentane has refractivity intercepts of at least 1.08 and moreparticularly, of at least 1.09, and still more particularly, of at least1.10.

(11) The oil separated from the polymers or resins after polymerizationusually has a density of not less than 0.95 and, more particularly, ofnot less than 0.98, for example, between 0.99 and 1.02 and higher, suchas up to 1.11 or 1.12. Such oils separated from the polymers or resinsafter polymerization also usually have refractivity intercepts of notless than 1.08, for example, between 1.09 and 1.11, and higher, such asup to 1.125 or 1.135, and contain at least such as at least and moreparticularly, at least 97 aromatic hydrocarbons.

(12) Reiractivity intercept when referred to herein is determined by themethod described in the Science of Petroleum (1938) vol. 2 beginning onpage 1175, and publications referred to therein.

While specific procedures have been particularly described, as well asthe units in which such depolymerization may be conducted, it is to beunderstood that these are by way of illustration. Therefore, changes,omissions, additions, substitutions, and/or modifications may be madewithin the scope of the claims without departing from the spirit of theinvention.

I claim:

1. A process for producing unsaturated. resinforming hydrocarbonmaterial comprising heating in a heating zone in attenuated form in thepresence of steam and under temperature conditions between 400 C. andand 800 C. and for a period of time sufficient to eiTectdepolymerization to unsaturated resin-forming material a solution in anaromatic hydrocarbon solvent substantially inert under the conditionsobtaining of mixed hydrocarbon resin polymer selected from the groupconsisting of heat resin polymer and catalytic resin polymer ofpolymerizable hydrocarbons contained in a hydrocarbon oil which has beenphysically separated from tar producedin the vapor phase pyrolysis ofpetroleum oil and which is free from and of greater volatility than thepitch of said tar, said hydrocarbon oil when separated and whensubjected to polymerization containing in addition to hydrocarbonsboiling between 210 C. and C.

which are not polymerizable by the application 'to said oil of heatalone but which are polymerizable to catalytic resin polymer by treatingsaid oil with a resin-producing catalyst, other hydrocarbons boilingbetween 210 C. and 450 C. which are polymerizable to catalytic resinpolymer by treating said oil with a resin-producing catalyst but whichlast-mentioned hydrocarbons are also polymerizable to heat resin polymerby the application to said oil of heat alone, said 1ast-men tionedhydrocarbons being present in said hydrocarbon oil in amount greaterthan approximately 5% of the total hydrocarbon oil boiling between 210C. and 450 C., while removing the resulting -depolymerized material fromsaid heating zone and cooling said removed material substantially asrapidly as formed, said steam being present in said heating zone in aproportion between 1 part steam to 10 parts resin polymer by weight and5 parts steam to 1 part resin polymer by weight;

and thereafter repolymerizing said removed depolymerized products inliquid phase.

2. A process for the production of hydrocarbon 15 heat resin polymercomprising heating in attenuated form and in solution in an aromatichydrocarbon solvent substantially inert under the conditions obtainingand under temperature conditions between and" C. and 868 C. and for aperiod or time sufficient to eiiect depolymeriza-- tion mixedhydrocarbon resin polymer selected from the group consisting of heatresin polymer and catalytic resin polymer of polymerizable hydrocarbonscontained in a hydrocarbon oil which has been physically separated fromtar produced in the vapor phase pyrolysis of petroieum oil and which isfree from and of greater volatility than the pitch of said tar, saidhydrocarbon oil when separated and when subjected to polymerizationcontainin in addition to hydrocarbons boiling between 2l0 C. and 450 C.which are not poiymerizable by the application to said oil of heat alonebut which are polymerizable to catalytic resin polymer by treating saidoil with a resin-producing catalyst, other hydrocarbons boiling between210 C. and 456 C. which are polymerizable to catalytic resin polymer bytreating said oil with a resin-producing catalyst but whichlast-mentioned hydrocarbons are also polymerizable to heat resin polymerby the application to oil of heat alone, said last-men tioneolhydrocarbons bein present in said hydrocarbon oil in amount greater thanapproximately 5% of the total hydrocarbon oil boiling between 210 C. and450 C., while removing the resulting depolymerized material from saidheating zone and cooling said removed material substantially as rapidlyas formed, said depolymerization being eiiected in the presence of steamin proportion between 1 part or steam to parts resin by weight and 5parts steam to 1 part resin by weight, and repoiymeriZing said removeddepolymerizecl material in liquid phase by the application of heat.

3. A process for the production of hydrocarbon catalytic resin polymercomprising heating in attenuated form and in solution in an aromatichydrocarbon solvent substantially inert under the conditions obtainingand under temperature conditions between ace 0. and 800 C. and for aperiod of time sufiicient to effect depolymerization mixed hydrocarbonresin polymer selected from the group consisting of heat resin polymerand catalytic resin polymer of polymerizable hydrocarbons contained in ahydrocarbon oil which has been physically separated from tar produced inthe vapor phase pyrolysis of petroleum oil and which is free from and ofgreater volatility than the pitcher said tar, said hydrocarbon oil whenseparated and when subjected to polymerization containing in addition tohydrocarbons boiling between 210 C. and 450 C. which are notpolymerizable by the application to said oil of heat alone but which arepolymerizable to catalytic resin polymer by treating said oil with aresin-producing catalyst, other hydrocarbons boiling between 210 C. and450 C. which are polymerizable to catalytic resin polymer by treatingsaid oil with a resin-producing catalyst but which last-mentionedhydrocarbons are also polymeriaable to heat resin polymer by theapplication to said oil of heat alone, said lastmentioned hydrocarbonsbeing present in said hydrocarbon oil in amount greater thanapproximately 5% of the total hydrocarbon .oil boiling between 210 C.and 4:50 C., while removing the resulting depolymerized material fromsaid heating zone and cooling said removed material substantially asrapidly as formed, said depolymerization being efiectecl in the presenceor steam in proportion between 1 part of steam to 10. parts resin byweight and 5 parts steam to 1 part resin by weight, and repolymerizingsaid removed depolymerized material in liquid phase by contact with aresin-producing catalyst.

A process for the production of hydrocarbon catalytic resin polymercomprising heating in attenuated form and in solution in an aromatichydrocarbon solvent substantially inert under the conditions obtainingand under temperature conditions between 400 C. and 800 C. and for aperiod of time sufiicient to enact depolyrnerization mixed hydrocarbonresin polymer selected from the group consisting of heat resin polymerand catalytic resin polymer of polymerizable hydrocarbons contained in ahydrocarbon oil which has been physically separated from tar produced inthe vapor phase pyrolysis of petroleum oil and which is free from and ofgreater volatility than the pitch oi said tar, said hydrocarbon oil whenseparated and when subjected. to polymerization containing in additionto hydrocarbons boiling between 210 C. and 450 C. which are not poly-.merizable by the application to said oil of heat alone but which arepolymerizable to catalytic resin polymer by treating said oil with aresinproducing catalyst, other hydrocarbons boiling between 210 C. and450 C. which are polymerizable to catalytic resin polymer by treatingsaid oil with a resin-producing catalyst but which last-mentionedhydrocarbons are also polymerizable to heat resin polymer by theapplication to said oil of heat alone, said last-mentioned hydrocarbonsbeing present in said hydrocarbon oil in amount greater thanapproximately 5% of the total hydrocarbonoil boiling between 210 C. and4 5.0 (3. which removing the resulting depolymerized material from saidheating zone and cooling said removed material substantially as rapidlyas formed, said depolymerization being effected in the presence of steamin proportion between 1 part of steam to 10 parts resin by weight and 5parts steam to 1 part resin by weight, and repolymerizing said removeddepolymerized material in liquid phase by contact with sulfuric acid.

5. The hydrocarbon heat resin polymer produced by the process of claim2.

6. The hydrocarbon sulfuric acid resin polymer produced by the process.of claim 4.

'2. The hydrocarbon resin polymer produced by the process of claim 1.

FRANK J. SODAY.

REFERENCES CITED The following references are of record in the file ofthis patent:

w UNITED STATES PATENTS Number Hall Oct. 23,

